Controlling device and controlling method for control within a predetermined energy consumption amount

ABSTRACT

A preferential upper limit processing section L_MH 1  limits the value of a pre-input manipulated variable output upper limit MH 1  so as to adjust a manipulated variable output MV 1  of a preferential controller PID 1  to a predetermined value MT 1  or less. A non-preferential upper limit calculating section C_MH 2  calculates a manipulated variable output upper limit MH 2  of a non-preferential controller PID 2  so as to adjust the sum of manipulated variable outputs MV 1  and MV 2  to the predetermined value MT 1  or less. A preferential upper limit calculating section C_MH 1  performs calculation of increasing/decreasing the manipulated variable output upper limit MH 1  of the controller PID 1  in accordance with the margin of the manipulated variable output MV 2  of the controller PID 2  with respect to the manipulated variable output upper limit value MH 2 , and sets the calculated value as a manipulated variable output upper limit value MH 1 ′ in the next control cycle.

The present patent application is a non-provisional application ofInternational Application No. PCT/JP01/06731, filed Aug. 6, 2001.

BACKGROUND OF THE INVENTION

The present invention relates to a controlling device and controllingmethod which perform control using a plurality of controllers within apredetermined energy consumption amount.

There has conventionally been known an apparatus (e.g., a semiconductormanufacturing apparatus using an electric heater as an actuator) whichhas a plurality of loops of a control system within one apparatus. Thisapparatus can prioritize and control the controllers of the respectivecontrol loops when the control characteristics of all the control loopsare not so important. Controlling the controllers with priorities cansuppress the power consumption amount (i.e., energy consumption amount).Assume that two control loops exist for a maximum heater output of 400W. If these two controllers are controlled without any priority, thepower equipment such as a power supply must provide 800 W; if thesecontrollers are prioritized and controlled, the power equipment can bedownsized.

Controllers are prioritized and controlled by a conventional method (tobe referred to as the first prior art hereinafter) of sequentiallyoperating them from a high-priority controller and operatinglower-priority controllers within the remaining ability (feedable poweramount). As another method, the abilities of controllers are lowered inaccordance with a controller having the lowest operation speed (to bereferred to as the second prior art hereinafter).

In the first prior art, a high-priority controller excessively takesprecedence, and a low-priority controller hardly functions, failing toobtain the controllability of the low-priority controller. To operateeven the low-priority controller, the ability of the overall apparatusmust be increased, resulting in a large energy consumption amount and abulky apparatus. In the first prior art, when controllers are set suchthat they operate within only fixed abilities designed in advance forthe respective controllers on the basis of priority, the usable abilityof the overall apparatus cannot be used up, leaving an unused ability.

In the second prior art, the ability of a high-priority controller iswasted. This means that a low-ability controller suffices to be usedfrom the first, and sacrifices the controllability.

SUMMARY OF THE INVENTION

The present invention has been made to overcome the conventionaldrawbacks, and has as its object to provide a controlling device andcontrolling method capable of satisfying both the controllability andenergy consumption amount of each controller within an acceptable range.

A controlling device according to the present invention comprises (1) apreferential controller (PID1) which calculates a manipulated variableoutput (MV1) in accordance with a first manipulated variable outputupper limit (MH1), (2) a non-preferential controller (PID2) whichcalculates a manipulated variable output (MV2) in accordance with asecond manipulated variable output upper limit (MH2), (3) a preferentialupper limit processing section (L_MH1) which limits a value of the firstmanipulated variable output upper limit input in advance and gives thefirst manipulated variable output upper limit to the preferentialcontroller so as to adjust the manipulated variable output of thepreferential controller to not more than a predetermined value (MT1)representing a manipulated variable output upper limit of a wholeapparatus, (4) a non-preferential upper limit calculating section(C_MH2) which calculates the second manipulated variable output upperlimit and gives the second manipulated variable output upper limit tothe non-preferential controller so as to adjust a sum of the manipulatedvariable outputs of the preferential and non-preferential controllers tonot more than the predetermined value, and (5) a preferential upperlimit calculating section (C_MH1) which performs calculation ofincreasing/decreasing the first manipulated variable output upper limitin accordance with a margin of the manipulated variable output of thenon-preferential controller with respect to the second manipulatedvariable output upper limit, and gives a calculated value as the firstmanipulated variable output upper limit (MH1′) in a next control cycleto the preferential upper limit processing section.

A controlling device according to the present invention comprises (1)first to mth controllers (PID1-PIDm) which are assigned first to mth (mis n−1) priorities in advance and calculate manipulated variable outputs(MV1-MVm) in accordance with first to mth corresponding manipulatedvariable output upper limits (MH1-MHm), (2) an nth controller (PIDn)which is assigned a lowest priority in advance and calculates amanipulated variable output (MVn) in accordance with an nth manipulatedvariable output upper limit (MHn), (3) first to mth preferential upperlimit processing sections (L_MH1-L_MHm) which are arranged for k (k isan integer of 1 to m) controllers, limit a value of a kth manipulatedvariable output upper limit input in advance, and give the k manipulatedvariable output upper limit to a kth controller so as to adjust a sum ofthe manipulated variable outputs of the first to kth controllers to notmore than a predetermined value (MT1) representing a manipulatedvariable output upper limit of a whole apparatus, (4) a non-preferentialupper limit calculating section (C_MHn) which calculates the nthmanipulated variable output upper limit and gives the nth manipulatedvariable output upper limit to the nth controller so as to adjust a sumof the manipulated variable outputs of the first to mth and nthcontrollers to not more than the predetermined value, and (5) first tomth preferential upper limit calculating sections (C_MH1-C_MHm) whichare arranged for the k controllers, perform calculation ofincreasing/decreasing the k manipulated variable output upper limit inaccordance with a margin of the manipulated variable outputs of a(k+1)th controller with respect to a (k+1)th manipulated variable outputupper limit, and give a calculated value as the kth manipulated variableoutput upper limit (MH1′-MHm′) in a next control cycle to a kthpreferential upper limit processing section.

As an arrangement example of the controlling device according to thepresent invention, the preferential upper limit calculating sectionincreases the first manipulated variable output upper limit when themanipulated variable output of the non-preferential controller has amargin with respect to the second manipulated variable output upperlimit, decreases the first manipulated variable output upper limit whenthe manipulated variable output does not have any margin, and changes adegree of decrease in accordance with priority of the preferentialcontroller with respect to the non-preferential controller.

As another arrangement example of the controlling device according tothe present invention, the kth preferential upper limit calculatingsection for the kth controller increases the kth manipulated variableoutput upper limit when the manipulated variable output of the (k+1)thcontroller has a margin with respect to the (k+1)th manipulated variableoutput upper limit, decreases the kth manipulated variable output upperlimit when the manipulated variable output does not have any margin, andchanges a degree of decrease in accordance with priority of the kthcontroller with respect to the (k+1)th controller.

In a controlling device which performs control using two, preferentialand non-preferential controllers within a predetermined energyconsumption amount, a control method according to the present inventioncomprises repetitively performing (1) preferential upper limitprocessing of limiting a value of a first manipulated variable outputupper limit (MH1) input in advance so as to adjust a manipulatedvariable output of the preferential controller (PID1) to not more than apredetermined value (MT1) representing a manipulated variable outputupper limit of a whole apparatus, (2) preferential manipulated variableoutput calculation processing of calculating a manipulated variableoutput (MV1) by the preferential controller in accordance with the firstmanipulated variable output upper limit, (3) non-preferential upperlimit calculation processing of calculating a second manipulatedvariable output upper limit (MH2) so as to adjust a sum of manipulatedvariable outputs of the preferential controller and the non-preferentialcontroller (PID2) to not more than the predetermined value, (4)non-preferential manipulated variable output calculation processing ofcalculating a manipulated variable output (MV2) by the non-preferentialcontroller in accordance with the second manipulated variable outputupper limit, and (5) preferential upper limit calculation processing ofperforming calculation of increasing/decreasing the first manipulatedvariable output upper limit in accordance with a margin of themanipulated variable output of the non-preferential controller withrespect to the second manipulated variable output upper limit, andgiving a calculated value as the first manipulated variable output upperlimit in a next control cycle to the preferential upper limitprocessing.

In a controlling device which performs control using n controllersassigned first to nth (n is an integer of not less than three)priorities in advance within a predetermined energy consumption amount,a control method according to the present invention comprises performing(1) first preferential upper limit processing of limiting a value of afirst manipulated variable output upper limit (MH1) input in advance soas to adjust a manipulated variable output of a first controller (PID1)to not more than a predetermined value (MT1) representing a manipulatedvariable output upper limit of a whole apparatus, (2) first preferentialmanipulated variable output calculation processing of calculating amanipulated variable output (MV1) by the first controller in accordancewith the first manipulated variable output upper limit, (3) secondpreferential upper limit processing of calculating a second manipulatedvariable output upper limit (MH2) so as to adjust a sum of manipulatedvariable outputs of the first controller and a second controller (PID2)to not more than the predetermined value, (4) second preferentialmanipulated variable output calculation processing of calculating amanipulated variable output (MV2) by the second controller in accordancewith the second manipulated variable output upper limit, and (5) firstpreferential upper limit calculation processing of performingcalculation of increasing/decreasing the first manipulated variableoutput upper limit in accordance with a margin of the manipulatedvariable output of the second controller with respect to the secondmanipulated variable output upper limit, and giving a calculated valueas the first manipulated variable output upper limit in a next controlcycle to the first preferential upper limit processing, sequentiallyperforming (6) three processes for i (i is an integer of 3 to m)controllers: ith preferential upper limit processing of limiting a valueof an ith manipulated variable output upper limit input in advance so asto adjust a sum of manipulated variable outputs of the first to ithcontrollers to not more than the predetermined value, ith preferentialmanipulated variable output calculation processing of calculating themanipulated variable output by the ith controller in accordance with theith manipulated variable output upper limit, and (i−1)th preferentialupper limit calculation processing of performing calculation ofincreasing/decreasing an (i−1)th manipulated variable output upper limitin accordance with a margin of the manipulated variable output of theith controller with respect to the ith manipulated variable output upperlimit, and giving a calculated value as the (i−1)th manipulated variableoutput upper limit in a next control cycle to the (i−1)th preferentialupper limit processing, performing (7) non-preferential upper limitcalculation processing of calculating an nth manipulated variable outputupper limit so as to adjust a sum of manipulated variable outputs of thefirst to mth and nth controllers to not more than the predeterminedvalue, (8) non-preferential manipulated variable output calculationprocessing of calculating a manipulated variable output (MVn) by the nthcontroller in accordance with the nth manipulated variable output upperlimit, and (9) mth preferential upper limit calculation processing ofperforming calculation of increasing/decreasing an mth manipulatedvariable output upper limit in accordance with a margin of themanipulated variable output of the nth controller with respect to thenth manipulated variable output upper limit, and giving a calculatedvalue as the mth manipulated variable output upper limit (MHm′) in anext control cycle to mth preferential upper limit processing, andrepetitively performing processing in (1) to (9).

As a processing example of the control method according to the presentinvention, the preferential upper limit calculation processing includesprocessing of increasing the first manipulated variable output upperlimit when the manipulated variable output of the non-preferentialcontroller has a margin with respect to the second manipulated variableoutput upper limit, decreasing the first manipulated variable outputupper limit when the manipulated variable output does not have anymargin, and changing a degree of decrease in accordance with priority ofthe preferential controller with respect to the non-preferentialcontroller.

As another processing example of the control method according to thepresent invention, kth preferential upper limit calculation processingfor the kth (k is an integer of 1 to m) controller includes processingof increasing the kth manipulated variable output upper limit when amanipulated variable output of the (k+1)th controller has a margin withrespect to the (k+1)th manipulated variable output upper limit,decreasing the kth manipulated variable output upper limit when themanipulated variable output does not have any margin, and changing adegree of decrease in accordance with priority of the kth controllerwith respect to the (k+1)th controller.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram showing the arrangement of a controllingdevice according to the first embodiment of the present invention;

FIG. 2 is a flow chart showing the operation of the controlling devicein FIG. 1;

FIG. 3 shows tables of control operation examples of the controllingdevice in FIG. 1;

FIG. 4 is a block diagram showing the arrangement of a controllingdevice according to the second embodiment of the present invention; and

FIG. 5 is a flow chart showing the operation of the controlling devicein FIG. 4.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[First Embodiment]

The first embodiment of the present invention will be described indetail below with reference to the accompanying drawings. FIG. 1 is ablock diagram showing the arrangement of a controlling device accordingto the first embodiment of the present invention. The controlling devicein FIG. 1 comprises a preferential controller PID1, non-preferentialcontroller PID2, preferential upper limit processing section L_MH1,non-preferential upper limit calculating section C_MH2, and preferentialupper limit calculating section C_MH1.

When the control characteristics of control loops are not so importantin an apparatus (semiconductor manufacturing apparatus or the like)having two loops of a control system using, e.g., an electric heater asan actuator in one apparatus, the first embodiment can be applied tothese two loops. In this case, the controller of a control loop whosecontrol characteristic is important is a preferential controller, andthe controller of a control loop whose control characteristic is not soimportant is a non-preferential controller.

The operation of the controlling device according to the firstembodiment will be explained. FIG. 2 is a flow chart showing theoperation of the controlling device in FIG. 1. The preferential upperlimit processing section L_MH1 compares a manipulated variable outputupper limit value MH1 representing the upper limit of a manipulatedvariable output MV1 from the preferential controller PID1 with apredetermined value MT1 (e.g., 100%) representing a preset manipulatedvariable output upper limit of the whole apparatus. If the manipulatedvariable output upper limit value MH1 is larger than the predeterminedvalue MT1, the preferential upper limit processing section L_MH1executes upper limit processing of setting MH1=MT1, i.e., setting thepredetermined value MT1 as a new manipulated variable output upper limitvalue MH1 (step 101 in FIG. 2).

The preferential upper limit processing section L_MH1 outputs theupdated manipulated variable output upper limit value MH1 to thepreferential controller PID1 and preferential upper limit calculatingsection C_MH1. If the manipulated variable output upper limit value MH1is equal to or smaller than the predetermined value MT1, thepreferential upper limit processing section L_MH1 need not update themanipulated variable output upper limit value MH1 and directly outputsthe current manipulated variable output upper limit value MH1. Thedefault value of the manipulated variable output upper limit value MH1in the first control cycle is set to, e.g., 100%.

The preferential controller PID1 executes PID calculation to calculatethe manipulated variable output MV1 (step 102).

In step 102, the preferential controller PID1 calculates by PIDcalculation an internal output value UC1 as a manipulated variablebefore upper limit processing based on the manipulated variable outputupper limit value MH1:UC 1=Kg 1{1+1/(Ti 1 s)+Td 1 s}(SP 1−PV 1)  (1)where Kg1 is the proportional gain of the controller PID1, Ti1 is theintegral time of the controller PID1, Td1 is the derivative time of thecontroller PID1, SP1 is the set point set for an object (not shown) tobe controlled by the controller PID1, and PV1 is the controlled variableof this object. The proportional gain Kg1, integral time Ti1, derivativetime Td1, and set point SP1 are set in advance, and the controlledvariable PV1 is detected by a sensor (not shown).

The preferential controller PID1 compares the calculated internal outputvalue UC1 and the manipulated variable output upper limit value MH1output from the preferential upper limit processing section L_MH1. Ifthe internal output value UC1 is larger than the manipulated variableoutput upper limit value MH1, the preferential controller PID1 executesupper limit processing of setting MV1=MH1, i.e., setting the manipulatedvariable output upper limit value MH1 as the manipulated variable outputMV1. If the internal output value UC1 is equal to or smaller than themanipulated variable output upper limit value MH1, the preferentialcontroller PID1 sets MV1=UC1, i.e., sets the internal output value UC1as the manipulated variable output MV1.

The preferential controller PID1 outputs the calculated manipulatedvariable output MV1 to the object to be controlled (not shown) and thenon-preferential upper limit calculating section C_MH2. At the sametime, the preferential controller PID1 outputs the internal output valueUC1 to the preferential upper limit calculating section C_MH1.

Processing in step 102 then ends.

The non-preferential upper limit calculating section C_MH2 calculates amanipulated variable output upper limit value MH2 representing the upperlimit of a manipulated variable output MV2 from the non-preferentialcontroller PID2, and outputs the manipulated variable output upper limitvalue MH2 to the non-preferential controller PID2 (step 103):MH 2=MT 1−MV 1  (2)

The non-preferential controller PID2 executes PID calculation tocalculate the manipulated variable output MV2 (step 104).

In step 104, the non-preferential controller PID2 calculates by PIDcalculation an internal output value UC2 as a manipulated variablebefore upper limit processing based on the manipulated variable outputupper limit value MH2:UC 2=Kg 2{1+1/(Ti 2 s)+Td 2 s}(SP 2−PV 2)  (3)where Kg2 is the proportional gain of the controller PID2, Ti2 is theintegral time of the controller PID2, Td2 is the derivative time of thecontroller PID2, SP2 is the set point set for an object (not shown) tobe controlled by the controller PID2, and PV2 is the controlled variableof this object. The proportional gain Kg2, integral time Ti2, derivativetime Td2, and set point SP2 are set in advance, and the controlledvariable PV2 is detected by a sensor (not shown).

The non-preferential controller PID2 compares the calculated internaloutput value UC2 and the manipulated variable output upper limit valueMH2 output from the non-preferential upper limit calculating sectionC_MH2. If the internal output value UC2 is larger than the manipulatedvariable output upper limit value MH2, the non-preferential controllerPID2 executes upper limit processing of setting MV2=MH2, i.e., settingthe manipulated variable output upper limit value MH2 as the manipulatedvariable output MV2. If the internal output value UC2 is equal to orsmaller than the manipulated variable output upper limit value MH2, thenon-preferential controller PID2 sets MV2=UC2, i.e., sets the internaloutput value UC2 as the manipulated variable output MV2.

The non-preferential controller PID2 outputs the calculated manipulatedvariable output MV2 to the object to be controlled (not shown) and thepreferential upper limit calculating section C_MH1. At the same time,the non-preferential controller PID2 outputs the internal output valueUC2 to the preferential upper limit calculating section C_MH1.

Processing in step 104 then ends.

The preferential upper limit calculating section C_MH1 calculates amanipulated variable output upper limit value MH1′ in the next controlcycle for the preferential controller PID1 (step 105).

In step 105, the preferential upper limit calculating section C_MH1checks whether the following inequality is established on the basis ofthe internal output value UC2 and manipulated variable output MV2 outputfrom the non-preferential controller PID2:α(UC 2−MV 2)>0  (4)where α is the priority coefficient representing the control priority ofthe preferential controller PID1 with respect to the non-preferentialcontroller PID2, and takes a real number of 0 to 1 (priority is highestfor 0, and lowest for 1).

If inequality (4) is established, the preferential upper limitcalculating section C_MH1 calculates by the following equation themanipulated variable output upper limit value MH1′ in the next controlcycle for the preferential controller PID1 on the basis of themanipulated variable output upper limit value MH1 in the current controlcycle output from the preferential upper limit processing section L_MH1,the internal output value UC1 output from the preferential controllerPID1, and the manipulated variable output MV2 and internal output valueUC2 output from the non-preferential controller PID2. The preferentialupper limit calculating section C_MH1 outputs the manipulated variableoutput upper limit value MH1′ to the preferential upper limit processingsection L_MH1:MH 1′=[MH 1 Tx 1+{UC 1−α(UC 2−MV 2)}dT]/(Tx 1+dT)  (5)where Tx1 is the transition time and, e.g., Tx1=Td1, and dT is thecontrol cycle.

If inequality (4) is not established, the preferential upper limitcalculating section C_MH1 calculates the manipulated variable outputupper limit value MH1′ on the basis of the predetermined value MT1, andthe manipulated variable output upper limit value MH1 in the currentcontrol cycle output from the preferential upper limit processingsection L_MH1, and outputs the manipulated variable output upper limitvalue MH1′ to the preferential upper limit processing section L_MH1:MH 1′=[MH 1 Tx 1+MT 1 dT]/(Tx 1+dT)  (6)

Processing in step 105 then ends.

Steps 101 to 105 are defined as processing in one control cycle, andprocessing from step 101 to step 105 is repeated every control cycle dT.

Note that the preferential upper limit processing section L_MH1 executesprocessing in step 101 by setting MH1=MH1′, i.e., setting, as themanipulated variable output upper limit value MH1 in the current controlcycle, the manipulated variable output upper limit value MH1′ calculatedand output from the preferential upper limit calculating section C_MH1in the preceding control cycle.

In this manner, in the first embodiment, the manipulated variable outputupper limit value MH2 of the non-preferential controller PID2 is set toMT1-MV1 (step 103) in order to always maintain the sum of themanipulated variable output MV1 of the preferential controller PID1 andthe manipulated variable output MV2 of the non-preferential controllerPID2 at the predetermined value MT1 (e.g., 100%) or less. If inequality(4) is not established, i.e., the internal output value UC2 of thenon-preferential controller PID2 has a margin with respect to themanipulated variable output upper limit value MH2 (UC2≦MH2), themanipulated variable output upper limit value MH1 of the preferentialcontroller PID1 is increased using equation (6) to make the manipulatedvariable output upper limit value MH1 asymptotically come close to thepredetermined value MT1 (step 105). As a result, the preferentialcontroller PID1 can output a larger manipulated variable output MV1. Atthis time, the transition time Tx1 is the time until the manipulatedvariable output upper limit value MH1 shifts to the predetermined valueMT1 (accurately, the manipulated variable output upper limit value MH1changes to 63.2% for a time of 100% between the manipulated variableoutput upper limit value MH1 and the predetermined value MT1).

If inequality (4) is established, i.e., the internal output value UC2 ofthe non-preferential controller PID2 does not have any margin withrespect to the manipulated variable output upper limit value MH2(UC2>MH2), the manipulated variable output upper limit value MH1 of thepreferential controller PID1 is asymptotically adjusted in a directionin which the manipulated variable output upper limit value MH1 decreasesby an output shortage (UC2−MV2) of the non-preferential controller PID2(step 105). This suppresses the manipulated variable output MV1 of thepreferential controller PID1. At this time, the transition time Tx1 isthe time until the manipulated variable output upper limit value MH1shifts to UC1−(UC2−MV2).

When inequality (4) is established and the manipulated variable outputupper limit value MH1 of the preferential controller PID1 is to bedecreased, the output shortage (UC2−MV2) of the non-preferentialcontroller PID2 serving as the decrease index is multiplied by thepriority coefficient α. By adjusting the value of the prioritycoefficient α, excessive precedence of the preferential controller PID1can be prevented, and the controllability of the non-preferentialcontroller PID2 can also be properly maintained within a possible range.

FIG. 3 shows tables of control operation examples of the controllingdevice according to the first embodiment. FIG. 3 shows the simulationresults of calculating the controlled variables PV1 and PV2 whendisturbance is applied in 600 sec and the set point SP1 of thepreferential controller PID1 is changed from 30% to 40% in 900 sec.

As shown in FIG. 3A, for the highest priority of the preferentialcontroller PID1 (α=0), control of the non-preferential controller PID2degrades when disturbance is applied in the first half of FIG. 3A andthe preferential set point SP1 is changed in the second half of FIG. 3A.However, control of the preferential controller PID1 responses fastest.

As shown in FIG. 3B, for the lowest priority of the preferentialcontroller PID1 (α=1), control of the non-preferential controller PID2does not greatly degrade when disturbance is applied in the first halfof FIG. 3B and the preferential set point SP1 is changed in the secondhalf of FIG. 3B. However, control of the preferential controller PID1responses slowly, compared to the fastest response.

In this way, the first embodiment can maintain the sum of themanipulated variable outputs MV1 and MV2 of two loops at thepredetermined value MT1 or less, and can maintain the high-prioritycontrolled variable PV1 in a good control state.

In the above-described application, the heater output may be given intime-proportional time division. For example, for two loops of a systemhaving a maximum heater output of 400 W, the sum of the manipulatedvariable outputs of the two loops is maintained at 100% or less. Thisrequires only a 400-W power equipment (energy supply source) such as apower supply, reducing the apparatus size and cost. If the presentinvention is not applied, an 800-W power equipment is required.

According to the first embodiment, the first manipulated variable outputupper limit value input in advance is limited and given to apreferential controller such that the manipulated variable output of thepreferential controller becomes equal to or smaller than a predeterminedvalue representing the manipulated variable output upper limit of thewhole apparatus. The second manipulated variable output upper limit iscalculated and given to a non-preferential controller such that the sumof the manipulated variable outputs of the preferential andnon-preferential controllers becomes equal to or smaller than thepredetermined value. Calculation of increasing/decreasing the firstmanipulated variable output upper limit in accordance with the margin ofthe manipulated variable output of the non-preferential controller withrespect to the second manipulated variable output upper limit isperformed. The calculated value is set as the first manipulated variableoutput upper limit in the next control cycle. Hence, goodcontrollability can be obtained for the preferential controller whilemaintaining the sum of the manipulated variable outputs of the two loopsat the predetermined value or less. The controllability of even thenon-preferential controller can also be maintained at a given degree.The controllability and energy consumption amount of each controller canbe satisfied within an acceptable range. As a result, thecontrollability of each controller and downsizing of the controllingdevice can be met. The usable ability of the controlling device can befully exploited. When the manipulated variable output of thenon-preferential controller does not have any margin with respect to thesecond manipulated variable output upper limit, the first manipulatedvariable output upper limit is decreased. The degree of decrease ischanged in accordance with the priority of the preferential controllerwith respect to the non-preferential controller. Excessive precedence ofthe preferential controller can be prevented, and even thecontrollability of the non-preferential controller can also be properlymaintained within a possible range.

[Second Embodiment]

FIG. 4 is a block diagram showing the arrangement of a controllingdevice according to the second embodiment of the present invention. Thecontrolling device in FIG. 4 comprises first to mth preferentialcontrollers PID1 to PIDm assigned the first to mth (m is an integer of 2or more) priorities, a non-preferential controller (nth controller) PIDnassigned the lowest priority in advance, first to mth preferential upperlimit processing sections L_MH1 to L_MHm respectively arranged incorrespondence with the preferential controllers PID1 to PIDm, anon-preferential upper limit calculating section C_MHn arranged incorrespondence with the non-preferential controller PIDn, and first tomth preferential upper limit calculating sections C_MH1 to C_MHmarranged in correspondence with the preferential controllers PID1 toPIDm.

When the control characteristics of control loops are not so importantin accordance with their priorities in an apparatus (semiconductormanufacturing apparatus or the like) having n (n is an integer of 3 ormore: n=m+1) loops of a control system using, e.g., an electric heateras an actuator in one apparatus, the second embodiment can be applied tothese n loops.

The operation of the controlling device according to the secondembodiment will be explained. FIG. 5 is a flow chart showing theoperation of the controlling device in FIG. 4. In this case, thepriority order is PID1, PID2, PID3, . . . , PIDm, and PIDn.

The first preferential upper limit processing section L_MH1 compares amanipulated variable output upper limit value MH1 of the firstpreferential controller PID1 having the highest priority with apredetermined value MT1 (e.g., 100%). If the manipulated variable outputupper limit value MH1 is larger than the predetermined value MT1, thefirst preferential upper limit processing section L_MH1 executes upperlimit processing of setting MH1=MT1, i.e., setting the predeterminedvalue MT1 as a new manipulated variable output upper limit value MH1(step 201 in FIG. 5).

The first preferential upper limit processing section L_MH1 outputs theupdated manipulated variable output upper limit value MH1 to the firstpreferential controller PID1 and first preferential upper limitcalculating section C_MH1. If the manipulated variable output upperlimit value MH1 is equal to or smaller than the predetermined value MT1,the first preferential upper limit processing section L_MH1 need notupdate the manipulated variable output upper limit value MH1 anddirectly outputs the current manipulated variable output upper limitvalue MH1.

The first preferential controller PID1 executes PID calculation tocalculate the manipulated variable output MV1 (step 202).

In step 202, the first preferential controller PID1 calculates aninternal output value UC1 by PID calculation:UC 1=Kg 1{1+1/(Ti 1 s)+Td 1 s}(SP 1−PV 1)  (7)

The first preferential controller PID1 compares the calculated internaloutput value UC1 and the manipulated variable output upper limit valueMH1 output from the first preferential upper limit processing sectionL_MH1. If the internal output value UC1 is larger than the manipulatedvariable output upper limit value MH1, the first preferential controllerPID1 executes upper limit processing of setting MV1=MH1, i.e., settingthe manipulated variable output upper limit value MH1 as the manipulatedvariable output MV1. If the internal output value UC1 is equal to orsmaller than the manipulated variable output upper limit value MH1, thefirst preferential controller PID1 sets MV1=UC1, i.e., sets the internaloutput value UC1 as the manipulated variable output MV1.

The first preferential controller PID1 outputs the calculatedmanipulated variable output MV1 to an object to be controlled (notshown) and the second preferential upper limit processing section L_MH2.At the same time, the first preferential controller PID1 outputs theinternal output value UC1 to the first preferential upper limitcalculating section C_MH1.

Processing in step 202 then ends.

The second preferential upper limit processing section L_MH2 calculatesan upper limit value MT2 for performing upper limit processing for amanipulated variable output upper limit value MH2 of the secondpreferential controller PID2 on the basis of the manipulated variableoutput MV1 output from the first preferential controller PID1 and thepredetermined value MT1 (step 203):MT 2=MT 1−MV 1  (8)

The second preferential upper limit processing section L_MH2 comparesthe manipulated variable output upper limit value MH2 of the secondpreferential controller PID2 and the upper limit value MT2. If themanipulated variable output upper limit value MH2 is larger than theupper limit value MT2, the second preferential upper limit processingsection L_MH2 sets MH2=MT2, i.e., the upper limit value MT2 as a newmanipulated variable output upper limit value MH2 (step 204).

The second preferential upper limit processing section L_MH2 outputs theupdated manipulated variable output upper limit value MH2 to the secondpreferential controller PID2 and second preferential upper limitcalculating section C_MH2. If the manipulated variable output upperlimit value MH2 is equal to or smaller than the upper limit value MT2,the second preferential upper limit processing section L_MH2 need notupdate the manipulated variable output upper limit value MH2, anddirectly outputs the current manipulated variable output upper limitvalue MH2.

The second preferential controller PID2 executes PID calculation tocalculate a manipulated variable output MV2 (step 205).

In step 205, the second preferential controller PID2 calculates aninternal output value UC2 by PID calculation:UC 2=Kg 2{1+1/(Ti 2 s)+Td 2 s}(SP 2−PV 2)  (9)

The second preferential controller PID2 compares the calculated internaloutput value UC2 and the manipulated variable output upper limit valueMH2 output from the second preferential upper limit processing sectionL_MH2. If the internal output value UC2 is larger than the manipulatedvariable output upper limit value MH2, the second preferentialcontroller PID2 executes upper limit processing of setting MV2=MH2,i.e., setting the manipulated variable output upper limit value MH2 asthe manipulated variable output MV2. If the internal output value UC2 isequal to or smaller than the manipulated variable output upper limitvalue MH2, the second preferential controller PID2 sets MV2=UC2, i.e.,sets the internal output value UC2 as the manipulated variable outputMV2.

The second preferential controller PID2 outputs the calculatedmanipulated variable output MV2 to an object to be controlled (notshown), the first preferential upper limit calculating section C_MH1,and the third preferential upper limit processing section L_MH3. At thesame time, the second preferential controller PID2 outputs the internaloutput value UC2 to the first preferential upper limit calculatingsection C_MH1 and second preferential upper limit calculating sectionC_MH2.

Processing in step 205 then ends.

The first preferential upper limit calculating section C_MH1 calculatesa manipulated variable output upper limit value MH1′ in the next controlcycle for the first preferential controller PID1 (step 206).

In step 206, the first preferential upper limit calculating sectionC_MH1 checks whether the following inequality is established on thebasis of the internal output value UC2 and manipulated variable outputMV2 output from the second preferential controller PID2:α1(UC 2−MV 2)>0  (10)where α1 is the priority coefficient representing the control priorityof the first preferential controller PID1 with respect to the secondpreferential controller PID2, and takes a real number of 0 to 1(priority is highest for 0, and lowest for 1).

If inequality (10) is established, the first preferential upper limitcalculating section C_MH1 calculates by the following equation themanipulated variable output upper limit value MH1′ in the next controlcycle for the first preferential controller PID1 on the basis of themanipulated variable output upper limit value MH1 in the current controlcycle output from the first preferential upper limit processing sectionL_MH1, the internal output value UC1 output from the first preferentialcontroller PID1, and the manipulated variable output MV2 and internaloutput value UC2 output from the second preferential controller PID2.The first preferential upper limit calculating section C_MH1 outputs themanipulated variable output upper limit value MH1′ to the firstpreferential upper limit processing section L_MH1:MH 1′=[MH 1 Tx 1+{UC 1−α1(UC 2−MV 2)}dT]/(Tx 1+dT)  (11)

If inequality (10) is not established, the first preferential upperlimit calculating section C_MH1 calculates the manipulated variableoutput upper limit value MH1′ on the basis of the predetermined valueMT1, and the manipulated variable output upper limit value MH1 in thecurrent control cycle output from the first preferential upper limitprocessing section L_MH1, and outputs the manipulated variable outputupper limit value MH1′ to the first preferential upper limit processingsection L_MH1:MH 1′=[MH 1 Tx 1+MT 1 dT]/(Tx 1+dT)  (12)

Processing in step 206 then ends.

The third preferential upper limit processing section L_MH3 calculatesan upper limit value MT3 for performing upper limit processing for amanipulated variable output upper limit value MH3 of the thirdpreferential controller PID3 on the basis of the manipulated variableoutput MV2 output from the second preferential controller PID2 and theupper limit value MT2 output from the second preferential upper limitprocessing section L_MH2 (step 207):MT 3=MT 2−MV 2  (13)

The third preferential upper limit processing section L_MH3 compares themanipulated variable output upper limit value MH3 of the thirdpreferential controller PID3 and the upper limit value MT3. If themanipulated variable output upper limit value MH3 is larger than theupper limit value MT3, the third preferential upper limit processingsection L_MH3 sets MH3=MT3, i.e., the upper limit value MT3 as a newmanipulated variable output upper limit value MH3 (step 208).

The third preferential upper limit processing section L_MH3 outputs theupdated manipulated variable output upper limit value MH3 to the thirdpreferential controller PID3 and third preferential upper limitcalculating section C_MH3. If the manipulated variable output upperlimit value MH3 is equal to or smaller than the upper limit value MT3,the third preferential upper limit processing section L_MH3 need notupdate the manipulated variable output upper limit value MH3, anddirectly outputs the current manipulated variable output upper limitvalue MH3.

The third preferential controller PID3 executes PID calculation tocalculate a manipulated variable output MV3 (step 209).

In step 209, the third preferential controller PID3 calculates aninternal output value UC3 by PID calculation:UC 3=Kg 3{1+1/(Ti 3 s)+Td 3 s}(SP 3−PV 3)  (14)where Kg3, Ti3, and Td3 are the proportional gain, integral time, andderivative time of the controller PID3, SP3 is the set point set for anobject (not shown) to be controlled by the controller PID3, and PV3 isthe controlled variable of this object. The proportional gain Kg3,integral time Ti3, derivative time Td3, and set point SP3 are set inadvance, and the controlled variable PV3 is detected by a sensor (notshown).

The third preferential controller PID3 compares the calculated internaloutput value UC3 and the manipulated variable output upper limit valueMH3 output from the third preferential upper limit processing sectionL_MH3. If the internal output value UC3 is larger than the manipulatedvariable output upper limit value MH3, the third preferential controllerPID3 executes upper limit processing of setting MV3=MH3, i.e., settingthe manipulated variable output upper limit value MH3 as the manipulatedvariable output MV3. If the internal output value UC3 is equal to orsmaller than the manipulated variable output upper limit value MH3, thethird preferential controller PID3 sets MV3=UC3, i.e., sets the internaloutput value UC3 as the manipulated variable output MV3.

The third preferential controller PID3 outputs the calculatedmanipulated variable output MV3 to an object to be controlled (notshown), the second preferential upper limit calculating section C_MH2,and the fourth preferential upper limit processing section L_MH4. At thesame time, the third preferential controller PID3 outputs the internaloutput value UC3 to the second preferential upper limit calculatingsection C_MH2 and third preferential upper limit calculating sectionC_MH3.

Processing in step 209 then ends.

The second preferential upper limit calculating section C_MH2 calculatesa manipulated variable output upper limit value MH2′ in the next controlcycle for the second preferential controller PID2 (step 210).

In step 210, the second preferential upper limit calculating sectionC_MH2 checks whether the following inequality is established on thebasis of the internal output value UC3 and manipulated variable outputMV3 output from the third preferential controller PID3:α2(UC 3−MV 3)>0  (15)where α2 is the priority coefficient representing the control priorityof the second preferential controller PID2 with respect to the thirdpreferential controller PID3, and takes a real number of 0 to 1(priority is highest for 0, and lowest for 1).

If inequality (15) is established, the second preferential upper limitcalculating section C_MH2 calculates by the following equation themanipulated variable output upper limit value MH2′ in the next controlcycle for the second preferential controller PID2 on the basis of themanipulated variable output upper limit value MH2 in the current controlcycle output from the second preferential upper limit processing sectionL_MH2, the internal output value UC2 output from the second preferentialcontroller PID2, and the manipulated variable output MV3 and internaloutput value UC3 output from the third preferential controller PID3. Thesecond preferential upper limit calculating section C_MH2 outputs themanipulated variable output upper limit value MH2′ to the secondpreferential upper limit processing section L_MH2:

 MH 2′=[MH 2 Tx 2+{UC 2−α2(UC 3−MV 3)}dT]/(Tx 2+dT)  (16)

where Tx2 is the transition time and, e.g., Tx2=Td2.

If inequality (15) is not established, the second preferential upperlimit calculating section C_MH2 calculates the manipulated variableoutput upper limit value MH2′ on the basis of the predetermined valueMT1, and the manipulated variable output upper limit value MH2 in thecurrent control cycle output from the second preferential upper limitprocessing section L_MH2, and outputs the manipulated variable outputupper limit value MH2′ to the second preferential upper limit processingsection L_MH2:MH 2′=[MH 2 Tx 2+MT 1 dT]/(Tx 2+dT)  (17)

Processing in step 210 then ends.

The same processes as those in steps 203 to 206 and 207 to 210 arerepeated, and the mth preferential upper limit calculating section C_MHmcalculates a manipulated variable output upper limit value MHm′ in thenext control cycle for the mth preferential controller PIDm. After that,the mth preferential upper limit processing section L_MHm calculates anupper limit value MTm for performing upper limit processing for amanipulated variable output upper limit value MHm of the mthpreferential controller PIDm on the basis of a manipulated variableoutput MVm−1 output from the (m−1)th preferential controller PIDm−1 andan upper limit value MTm−1 output from the (m−1)th preferential upperlimit processing section L_MHm−1 (not shown) (step 300):MTm=MTm−1−MVm−1  (18)

The mth preferential upper limit processing section L_MHm compares themanipulated variable output upper limit value MHm of the mthpreferential controller PIDm and the upper limit value MTm. If themanipulated variable output upper limit value MHm is larger than theupper limit value MTm, the mth preferential upper limit processingsection L_MHm sets MHm=MTm, i.e., the upper limit value MTm as a newmanipulated variable output upper limit value MHm (step 301).

The mth preferential upper limit processing section L_MHm outputs theupdated manipulated variable output upper limit value MHm to the mthpreferential controller PIDm and mth preferential upper limitcalculating section C_MHm. If the manipulated variable output upperlimit value MHm is equal to or smaller than the upper limit value MTm,the mth preferential upper limit processing section L_MHm need notupdate the manipulated variable output upper limit value MHm, anddirectly outputs the current manipulated variable output upper limitvalue MHm.

The mth preferential controller PIDm executes PID calculation tocalculate a manipulated variable output MVm (step 302).

In step 302, the mth preferential controller PIDm calculates an internaloutput value UCm by PID calculation:UCm=Kgm{1+1/(Tim s)+Tdm s}(SPm−PVm)  (19)where Kgm, Tim, and Tdm are the proportional gain, integral time, andderivative time of the controller PIDm, SPm is the set point set for anobject (not shown) to be controlled by the controller PIDm, and PVm isthe controlled variable of this object. The proportional gain Kgm,integral time Tim, derivative time Tdm, and set point SPm are set inadvance, and the controlled variable PVm is detected by a sensor (notshown).

The mth preferential controller PIDm compares the calculated internaloutput value UCm and the manipulated variable output upper limit valueMHm output from the mth preferential upper limit processing sectionL_MHm. If the internal output value UCm is larger than the manipulatedvariable output upper limit value MHm, the mth preferential controllerPIDm executes upper limit processing of setting MVm=MHm, i.e., settingthe manipulated variable output upper limit value MHm as the manipulatedvariable output MVm. If the internal output value UCm is equal to orsmaller than the manipulated variable output upper limit value MHm, themth preferential controller PIDm sets MVm=UCm, i.e., sets the internaloutput value UCm as the manipulated variable output MVm.

The mth preferential controller PIDm outputs the calculated manipulatedvariable output MVm to an object to be controlled (not shown), the(m−1)th preferential upper limit calculating section C_MHm−1, and thenon-preferential upper limit calculating section C_MHn. At the sametime, the mth preferential controller PIDm outputs the internal outputvalue UCm to the (m−1)th preferential upper limit calculating sectionC_MHm−1 and mth preferential upper limit calculating section C_MHm.

Processing in step 302 then ends.

The (m−1)th preferential upper limit calculating section C_MHm−1calculates a manipulated variable output upper limit value MHm−1′ in thenext control cycle for the (m−1)th preferential controller PIDm−1 (step303).

In step 303, the (m−1)th preferential upper limit calculating sectionC_MHm−1 checks whether the following inequality is established on thebasis of the internal output value UCm and manipulated variable outputMVm output from the mth preferential controller PIDm:αm−1(UCm−Mvm)>0  (20)where αm−1 is the priority coefficient representing the control priorityof the (m−1)th preferential controller PIDm−1 with respect to the mthpreferential controller PIDm, and takes a real number of 0 to 1(priority is highest for 0, and lowest for 1).

If inequality (20) is established, the (m−1)th preferential upper limitcalculating section C_MHm−1 calculates by the following equation themanipulated variable output upper limit value MHm−1′ in the next controlcycle for the (m−1)th preferential controller PIDm−1 on the basis of themanipulated variable output upper limit value MHm−1 in the currentcontrol cycle output from the (m−1)th preferential upper limitprocessing section L_MHm−1, the internal output value UCm−1 output fromthe (m−1)th preferential controller PIDm−1, and the manipulated variableoutput MVm and internal output value UCm output from the mthpreferential controller PIDm. The (m−1)th preferential upper limitcalculating section C_MHm−1 outputs the manipulated variable outputupper limit value MHm−1′ to the (m−1)th preferential upper limitprocessing section L_MHm−1:MHm−1′=[MHm−1Txm−1+{UCm−1−αm−1(UCm−MVm)}dT]/(Txm−1+dT)  (21)where Txm−1 is the transition time and, e.g., Txm−1=Tdm−1.

If inequality (20) is not established, the (m−1)th preferential upperlimit calculating section C_MHm−1 calculates the manipulated variableoutput upper limit value MHm−1′ on the basis of the predetermined valueMT1, and the manipulated variable output upper limit value MHm−1 in thecurrent control cycle output from the (m−1)th preferential upper limitprocessing section L_MHm−1, and outputs the manipulated variable outputupper limit value MHm−1′ to the (m−1)th preferential upper limitprocessing section L_MHm−1:MHm−1′=[MHm−1Txm−1+MT 1 dT]/(Txm−1+dT)  (22)

Processing in step 303 then ends.

The non-preferential upper limit calculating section C_MHn calculates amanipulated variable output upper limit value MHn representing the upperlimit of a manipulated variable output MVn from the non-preferentialcontroller PIDn on the basis of the manipulated variable output MVmoutput from the mth preferential controller PIDm and the upper limitvalue MTm output from the mth preferential upper limit processingsection L_MHm, and outputs the manipulated variable output upper limitvalue MHn to the non-preferential controller PIDn (step 304):MHn=MTm−MVm  (23)

The non-preferential controller PIDn executes PID calculation tocalculate the manipulated variable output MVn (step 305).

In step 305, the non-preferential controller PIDn calculates an internaloutput value UCn by PID calculation:UCn=Kgn{1+1/(Tin s)+Tdn s}(SPn−PVn)  (24)where Kgn, Tin, and Tdn are the proportional gain, integral time, andderivative time of the controller PIDn, SPn is the set point set for anobject (not shown) to be controlled by the controller PIDn, and PVn isthe controlled variable of this object. The proportional gain Kgn,integral time Tin, derivative time Tdn, and set point SPn are set inadvance, and the controlled variable PVn is detected by a sensor (notshown).

The non-preferential controller PIDn compares the calculated internaloutput value UCn and the manipulated variable output upper limit valueMHn output from the non-preferential upper limit calculating sectionC_MHn. If the internal output value UCn is larger than the manipulatedvariable output upper limit value MHn, the non-preferential controllerPIDn executes upper limit processing of setting MVn=MHn, i.e., settingthe manipulated variable output upper limit value MHn as the manipulatedvariable output MVn. If the internal output value UCn is equal to orsmaller than the manipulated variable output upper limit value MHn, thenon-preferential controller PIDn sets MVn=UCn, i.e., sets the internaloutput value UCn as the manipulated variable output MVn.

The non-preferential controller PIDn outputs the calculated manipulatedvariable output MVn to the object to be controlled (not shown) and themth preferential upper limit calculating section C_MHm. At the sametime, the non-preferential controller PIDn outputs the internal outputvalue UCn to the preferential upper limit calculating section C_MHm.

Processing in step 305 then ends.

The mth preferential upper limit calculating section C_MHm calculates amanipulated variable output upper limit value MHm′ in the next controlcycle for the mth preferential controller PIDm (step 306).

In step 306, the preferential upper limit calculating section C_MHmchecks whether the following inequality is established on the basis ofthe internal output value UCn and manipulated variable output MVn outputfrom the non-preferential controller PIDn:αm(UCn−MVn)>0  (25)where αm is the priority coefficient representing the control priorityof the mth preferential controller PIDm with respect to thenon-preferential controller PIDn, and takes a real number of 0 to 1(priority is highest for 0, and lowest for 1).

If inequality (25) is established, the mth preferential upper limitcalculating section C_MHm calculates by the following equation themanipulated variable output upper limit value MHm′ in the next controlcycle for the preferential controller PIDm on the basis of themanipulated variable output upper limit value MHm in the current controlcycle output from the mth preferential upper limit processing sectionL_MHm, the internal output value UCm output from the mth preferentialcontroller PIDm, and the manipulated variable output MVn and internaloutput value UCn output from the non-preferential controller PIDn. Themth preferential upper limit calculating section C_MHm outputs themanipulated variable output upper limit value MHm′ to the mthpreferential upper limit processing section L_MHm:MHm′=[MHm Txm+{UCm−αm(UCn−MVn)}dT]/(Txm+dT)  (26)where Txm is the transition time and, e.g., Txm=Tdm.

If inequality (25) is not established, the preferential upper limitcalculating section C_MHm calculates the manipulated variable outputupper limit value MHm′ on the basis of the predetermined value MT1, andthe manipulated variable output upper limit value MHm in the currentcontrol cycle output from the mth preferential upper limit processingsection L_MHm, and outputs the manipulated variable output upper limitvalue MHm′ to the preferential upper limit processing section L_MHm:MHm′=[MHm Txm+MT 1 dT]/(Txm+dT)  (27)

Processing in step 306 then ends.

Steps 201 to 306 are defined as processing in one control cycle, andprocessing from step 201 to step 306 is repeated every control cycle dT.

Note that the ith (i=1 to m) preferential upper limit processing sectionL_MHi executes processes in steps 201, 204, 208, and 301 by settingMHi=MHi′, i.e., setting, as the manipulated variable output upper limitvalue MHi in the current control cycle, the manipulated variable outputupper limit value MHi′ calculated and output from the ith preferentialupper limit calculating section C_MHi in the preceding control cycle.

In this fashion, in the second embodiment, the manipulated variableoutput upper limit value MH2 of the second preferential controller PID2is set to MT1-MV1 (step 203), . . . , the manipulated variable outputupper limit value MH3 of the third preferential controller PID3 is setto MT1-MV1-MV2 (step 207), . . . , the manipulated variable output upperlimit value MHn of the non-preferential controller PIDn is set toMTm-MVm (step 304) in order to always maintain the sum of themanipulated variable output MV1 of the first preferential controllerPID1, the manipulated variable output MV2 of the second preferentialcontroller PID2, . . . , the output MVn of the non-preferentialcontroller PIDn at the predetermined value MT1 or less.

If inequality (10) is not established, i.e., the internal output valueUC2 of the non-preferential controller PID2 has a margin with respect tothe manipulated variable output upper limit value MH2 (UC2≦MH2), themanipulated variable output upper limit value MH1 of the firstpreferential controller PID1 is increased using equation (12) to makethe manipulated variable output upper limit value MH1 asymptoticallycome close to the predetermined value MT1 (step 206). As a result, thefirst preferential controller PID1 can output a larger manipulatedvariable output MV1.

If inequality (10) is established, i.e., the internal output value UC2of the second preferential controller PID2 does not have any margin withrespect to the manipulated variable output upper limit value MH2(UC2>MH2), the manipulated variable output upper limit value MH1 of thefirst preferential controller PID1 is asymptotically adjusted in adirection in which the manipulated variable output upper limit value MH1decreases by an output shortage (UC2−MV2) of the second preferentialcontroller PID2 (step 206). This suppresses the manipulated variableoutput MV1 of the first preferential controller PID1. When inequality(10) is established and the manipulated variable output upper limitvalue MH1 of the first preferential controller PID1 is to be decreased,the output shortage (UC2−MV2) of the second preferential controller PID2serving as the decrease index is multiplied by the priority coefficientα1. By adjusting the value of the priority coefficient α1, excessiveprecedence of the first preferential controller PID1 can be prevented,and the controllability of the second preferential controller PID2 canalso be properly maintained within a possible range.

Similarly, when the manipulated variable output MVj+1 of the (j+1)thcontroller PIDj+1 has a margin with respect to the (j+1)th (j is aninteger of 2 to m) manipulated variable output upper limit MHj+1, themanipulated variable output upper limit MHj of the jth controller PID1is increased to make the manipulated variable output upper limit MHjasymptotically come close to the predetermined value MT1. Thus, the jthcontroller PIDj can output a larger manipulated variable output MVj.

When the manipulated variable output MVj+1 of the (j+1)th controllerPIDj+1 does not have any margin with respect to the (j+1)th manipulatedvariable output upper limit MHj+1, the manipulated variable output upperlimit MHj of the jth controller PIDj is asymptotically adjusted in adirection in which the manipulated variable output upper limit MHjdecreases by an output shortage (UCj+1−MVj+1) of the (j+1)th controllerPIDj+1. This suppresses the manipulated variable output MVj of the jthcontroller PIDj.

In decreasing the manipulated variable output upper limit value MHj ofthe jth controller PIDj, the output shortage (UCj+1−MVj+1) of the(j+1)th controller PIDj+1 serving as the decrease index is multiplied bythe priority coefficient αj. By adjusting the value of the prioritycoefficient αj, excessive precedence of the jth controller PIDj can beprevented, and the controllability of the (j+1)th controller PIDj+1 canalso be properly maintained within a possible range.

In this way, the second embodiment can maintain the sum of themanipulated variable outputs MV1, MV2, . . . , MVn of n loops at thepredetermined value MT1 or less, and can maintain a high-prioritycontrolled variable in a good control state.

In the above-described application, the heater output may be given intime-proportional time division. For example, for four loops of a systemhaving a maximum heater output of 400 W, the sum of the manipulatedvariable outputs of the four loops is maintained at 100% or less. Thisrequires only a 400-W power equipment such as a power supply, reducingthe apparatus size and cost. If the present invention is not applied, a1,600-W power equipment is required.

In the second embodiment, the manipulated variable output upper limitvalues MH1, MH2, MH3, . . . , MHm in the first control cycle are set to,e.g., 100%.

According to the second embodiment, the kth manipulated variable outputupper limit value input in advance is limited and given to the kthcontroller such that the sum of the manipulated variable outputs of thefirst to kth (k is an integer of 1 to m) controllers becomes equal to orsmaller than a predetermined value representing the manipulated variableoutput upper limit of the whole apparatus. The nth manipulated variableoutput upper limit is calculated and given to the nth controller suchthat the sum of the manipulated variable outputs of the first to mth andnth controllers becomes equal to or smaller than the predeterminedvalue. Calculation of increasing/decreasing the kth manipulated variableoutput upper limit in accordance with the margin of the manipulatedvariable output of the (k+1)th controller with respect to the (k+1)thmanipulated variable output upper limit is performed. The calculatedvalue is set as the kth manipulated variable output upper limit in thenext control cycle. Hence, good controllability can be obtained for thepreferential controller while maintaining the sum of the manipulatedvariable outputs of the n loops at the predetermined value or less. Thecontrollability of even the non-preferential controller can also bemaintained at a given degree. The controllability and energy consumptionamount of each controller can be satisfied within an acceptable range.As a result, the controllability of each controller and downsizing ofthe controlling device can be met. The usable ability of the controllingdevice can be fully exploited. When the manipulated variable output ofthe (k+1)th controller does not have any margin with respect to the(k+1)th manipulated variable output upper limit, the kth manipulatedvariable output upper limit is decreased. The degree of decrease ischanged in accordance with the priority of the kth controller withrespect to the (k+1)th controller. Excessive precedence of the kthcontroller can be prevented, and even the controllability of the (k+1)thcontroller can also be properly maintained within a possible range.

As has been described above, the present invention is suitable forcontrol using a plurality of controllers.

1. A controlling device which performs control using two controllerswithin a predetermined energy consumption amount, characterized bycomprising: (1) a preferential controller which calculates a manipulatedvariable output in accordance with a first manipulated variable outputupper limit; (2) a non-preferential controller which calculates amanipulated variable output in accordance with a second manipulatedvariable output upper limit; (3) a preferential upper limit processingsection which limits a value of the first manipulated variable outputupper limit input in advance and gives the first manipulated variableoutput upper limit to said preferential controller so as to adjust themanipulated variable output of said preferential controller to not morethan a predetermined value representing a manipulated variable outputupper limit of a whole apparatus; (4) a non-preferential upper limitcalculating section which calculates the second manipulated variableoutput upper limit and gives the second manipulated variable outputupper limit to said non-preferential controller so as to adjust a sum ofthe manipulated variable outputs of said preferential andnon-preferential controllers to not more than the predetermined value;and (5) a preferential upper limit calculating section which performscalculation of increasing/decreasing the first manipulated variableoutput upper limit in accordance with a margin of the manipulatedvariable output of said non-preferential controller with respect to thesecond manipulated variable output upper limit, and gives a calculatedvalue as the first manipulated variable output upper limit in a nextcontrol cycle to said preferential upper limit processing section.
 2. Acontrolling device according to claim 1, characterized in that saidpreferential upper limit calculating section increases the firstmanipulated variable output upper limit when the manipulated variableoutput of said non-preferential controller has a margin with respect tothe second manipulated variable output upper limit, decreases the firstmanipulated variable output upper limit when the manipulated variableoutput does not have any margin, and changes a degree of decrease inaccordance with priority of said preferential controller with respect tosaid non-preferential controller.
 3. A controlling device which performscontrol using n (n is an integer of not less than three) controllerswithin a predetermined energy consumption amount, characterized bycomprising: (1) first to mth controllers which are assigned first to mth(m is n−1) priorities in advance and calculate manipulated variableoutputs in accordance with first to mth corresponding manipulatedvariable output upper limits; (2) an nth controller which is assigned alowest priority in advance and calculates a manipulated variable outputin accordance with an nth manipulated variable output upper limit; (3)first to mth preferential upper limit processing sections which arearranged for k (k is an integer of 1 to m) controllers, limit a value ofa kth manipulated variable output upper limit input in advance, and givethe k manipulated variable output upper limit to a kth controller so asto adjust a sum of the manipulated variable outputs of said first to kthcontrollers to not more than a predetermined value representing amanipulated variable output upper limit of a whole apparatus; (4) anon-preferential upper limit calculating section which calculates thenth manipulated variable output upper limit and gives the nthmanipulated variable output upper limit to said nth controller so as toadjust a sum of the manipulated variable outputs of said first to mthand nth controllers to not more than the predetermined value; and (5)first to mth preferential upper limit calculating sections which arearranged for the k controllers, perform calculation ofincreasing/decreasing the k manipulated variable output upper limit inaccordance with a margin of the manipulated variable outputs of a(k+1)th controller with respect to a (k+1)th manipulated variable outputupper limit, and give a calculated value as the kth manipulated variableoutput upper limit in a next control cycle to a kth preferential upperlimit processing section.
 4. A controlling device according to claim 3,characterized in that said kth preferential upper limit calculatingsection for said kth controller increases the kth manipulated variableoutput upper limit when the manipulated variable output of said (k+1)thcontroller has a margin with respect to the (k+1)th manipulated variableoutput upper limit, decreases the kth manipulated variable output upperlimit when the manipulated variable output does not have any margin, andchanges a degree of decrease in accordance with priority of said kthcontroller with respect to said (k+1)th controller.
 5. In a controllingdevice which performs control using two, preferential andnon-preferential controllers within a predetermined energy consumptionamount, a control method characterized by comprising repetitivelyperforming: (1) preferential upper limit processing of limiting a valueof a first manipulated variable output upper limit input in advance soas to adjust a manipulated variable output of the preferentialcontroller to not more than a predetermined value representing amanipulated variable output upper limit of a whole apparatus; (2)preferential manipulated variable output calculation processing ofcalculating a manipulated variable output by the preferential controllerin accordance with the first manipulated variable output upper limit;(3) non-preferential upper limit calculation processing of calculating asecond manipulated variable output upper limit so as to adjust a sum ofmanipulated variable outputs of the preferential and non-preferentialcontrollers to not more than the predetermined value; (4)non-preferential manipulated variable output calculation processing ofcalculating a manipulated variable output by the non-preferentialcontroller in accordance with the second manipulated variable outputupper limit; and (5) preferential upper limit calculation processing ofperforming calculation of increasing/decreasing the first manipulatedvariable output upper limit in accordance with a margin of themanipulated variable output of the non-preferential controller withrespect to the second manipulated variable output upper limit, andgiving a calculated value as the first manipulated variable output upperlimit in a next control cycle to the preferential upper limitprocessing.
 6. A controlling method according to claim 5, characterizedin that the preferential upper limit calculation processing includesprocessing of increasing the first manipulated variable output upperlimit when the manipulated variable output of the non-preferentialcontroller has a margin with respect to the second manipulated variableoutput upper limit, decreasing the first manipulated variable outputupper limit when the manipulated variable output does not have anymargin, and changing a degree of decrease in accordance with priority ofthe preferential controller with respect to the non-preferentialcontroller.
 7. In a controlling device which performs control using ncontrollers assigned first to nth (n is an integer of not less thanthree) priorities in advance within a predetermined energy consumptionamount, a control method characterized by comprising: performing (1)first preferential upper limit processing of limiting a value of a firstmanipulated variable output upper limit input in advance so as to adjusta manipulated variable output of a first controller to not more than apredetermined value representing a manipulated variable output upperlimit of a whole apparatus, (2) first preferential manipulated variableoutput calculation processing of calculating a manipulated variableoutput by the first controller in accordance with the first manipulatedvariable output upper limit, (3) second preferential upper limitprocessing of calculating a second manipulated variable output upperlimit so as to adjust a sum of manipulated variable outputs of the firstcontroller and a second controller to not more than the predeterminedvalue, (4) second preferential manipulated variable output calculationprocessing of calculating a manipulated variable output by the secondcontroller in accordance with the second manipulated variable outputupper limit, and (5) first preferential upper limit calculationprocessing of performing calculation of increasing/decreasing the firstmanipulated variable output upper limit in accordance with a margin ofthe manipulated variable output of the second controller with respect tothe second manipulated variable output upper limit, and giving acalculated value as the first manipulated variable output upper limit ina next control cycle to the first preferential upper limit processing;sequentially performing (6) three processes for i (i is an integer of 3to m) controllers: ith preferential upper limit processing of limiting avalue of an ith manipulated variable output upper limit input in advanceso as to adjust a sum of manipulated variable outputs of the first toith controllers to not more than the predetermined value, ithpreferential manipulated variable output calculation processing ofcalculating the manipulated variable output by the ith controller inaccordance with the ith manipulated variable output upper limit, and(i−1)th preferential upper limit calculation processing of performingcalculation of increasing/decreasing an (i−1)th manipulated variableoutput upper limit in accordance with a margin of the manipulatedvariable output of the ith controller with respect to the ithmanipulated variable output upper limit, and giving a calculated valueas the (i−1)th manipulated variable output upper limit in a next controlcycle to the (i−1)th preferential upper limit processing; performing (7)non-preferential upper limit calculation processing of calculating annth manipulated variable output upper limit so as to adjust a sum ofmanipulated variable outputs of the first to mth and nth controllers tonot more than the predetermined value, (8) non-preferential manipulatedvariable output calculation processing of calculating a manipulatedvariable output by the nth controller in accordance with the nthmanipulated variable output upper limit, and (9) mth preferential upperlimit calculation processing of performing calculation ofincreasing/decreasing an mth manipulated variable output upper limit inaccordance with a margin of the manipulated variable output of the nthcontroller with respect to the nth manipulated variable output upperlimit, and giving a calculated value as the mth manipulated variableoutput upper limit in a next control cycle to mth preferential upperlimit processing; and repetitively performing processing in (1) to (9).8. A controlling method according to claim 7, characterized in that kthpreferential upper limit calculation processing for the kth (k is aninteger of 1 to m) controller includes processing of increasing the kthmanipulated variable output upper limit when a manipulated variableoutput of the (k+1)th controller has a margin with respect to the(k+1)th manipulated variable output upper limit, decreasing the kthmanipulated variable output upper limit when the manipulated variableoutput does not have any margin, and changing a degree of decrease inaccordance with priority of the kth controller with respect to the(k+1)th controller.